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TOPIC: Roof Pitch

standing seam and mechanical sealing

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I'm planning to replace a shingle roof and want to replace it with metal if we can work out the issues (including paying for it). The existing roof is about a 2.5/12 pitch, hipped. At one end are several odd bits, partly due to a breezeway and garage on the original 1953 house, partly due to the garage conversion (a religion in our neighborhood) and addition of a carport (flat) and porch (homeowner job with a zero-pitch valley). Due to these problems, I want to have the roof structure rebuilt to reduce the number of slopes and valleys and create additional overhang in front, where there's currently no way to get from the front door to the carport without getting wet when it's raining, and this is in north Florida. However, the simplest roof would involve a pitch just over 2/12. Keeping the pitch at a minimum 2.5/12 would require additional slopes, ridges, and/or valleys. I've read a lot of the threads here, and I've reading conflicting information about the point at which mechanically sealed standing seam is required. Sometimes I read 3/12, sometimes 2/12, sometimes 2.5/12. I'm guessing that this varies by manufacturer. Is this correct, or is it more complicated? And am I correct that any metal roof at these pitches will have to be standing seam, whether mechanically sealed or not? Finally, is there a rule of thumb I can apply to the cost of mechanical sealing? I know you don't discuss costs in general here, but I'm wondering if there's some percentage I can apply just to tell us whether to pursue this roof design or to try to design with higher slopes. So that's three questions: pitch where mechanical sealing is required, pitch where standing seam is required, and relative cost of mechanical sealing. Thanks, Edward
Edward Reid

8/20/2009
There are some non mechanical seamed panels out there that can be used down to 2:12. There is some dependence upon the roof configuration as well and how much water will be carried by the panels. Generally speaking there will not be much difference in price between a snap lock system and a mechanically seamed one.
Todd Miller
Isaiah Industries, Inc.

8/29/2009